Use of inositol triphosphate as a stabilizer and compositions formed therefrom

ABSTRACT

An organic substrate, such as a pharmaceutical or biological system subject to degradation by oxidation and/or free radical formation, is stabilized by various inositol triphosphate compounds.

REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of U.S. patent application, Ser. No. 788,830 filed Oct. 18, 1985, now U.S. Pat. No. 4,735,902.

The present invention relates to a stabilized composition comprising an organic substrate, such as a pharmaceutical or biological system subject to degradation by oxidation and/or free radicals, and a method for production thereof.

It is well-known that biological materials and pharmaceuticals often have a rather limited stability even if they are stored in a dark and cold space. Among the pharmaceuticals having such a low stability, insulin, vaccine, hyaluronic acid, intralipid and prostaglandin can be mentioned. In addition, many other organic substrates susceptible to oxidative or free radical degradation are well-known to those skilled in the art and include e.g., fats, oils, ethylenically unsaturated compounds, derivatives and polymers e.g. acrylate compounds and resins, polyvinylacetate, polyvinylpyrrolidone, vinylacetate, vinylpyrrolidone and the like.

It is well-known that the formation of free radicals during storing and/or use of many pharmaceuticals and biological materials causes a degradation of these products. The free radicals namely cause an oxidation, which in its turn results in a degradation of the pharmaceutical or the biological material. Similar mechanisms are responsible for the lack of stability of other organic substrates, such as those mentioned above.

Accordingly, the presence of free radicals can explain why hyaluronic acid for example is effective at application of eyes but not at injection in joints for treatment of rheumatism. Free radicals are formed in the eyes to a slight extent. However, on the other hand, in the joints, free radicals are formed in a considerable amount. Therefore, the hyaluronic acid is broken down or degraded by free radicals in the joint fluids before it has given the desired effect.

In addition to the negative effect on the stability of pharmaceuticals and biological materials, free radicals can also increase the toxicity of said products, which of course is a very serious problem.

A very intensive research effort has been carried out for many years to find an effective and non-toxic stabilizer for organic substrates, such as pharmaceuticals and biological materials. In general, said work has not given the desired result.

In the U.S. Pat. No. 2,723,938 another kind of stabilization than that according to the present invention is disclosed. Thus, according to said patent the use of inositolhexaphosphates (IP₆), especially sodium phytate for stabilizing dispersability of aqueous suspensions of insoluble penicillin even after prolonged storage is shown. The use of said sodium phytate is said to insure that brief manual shaking will restore a state of complete and uniform dispersion of the penicillin. However, no effectiveness in stabilization against oxidative degradation caused by free radicals is reported. When compared with IP₃ stabilizers of this invention, IP₆ is found to be less effective as a stabilizer against degradation of organic substrates. In addition, the use of IP₆ is also seriously limited because of the impact on the mineral balance in animals including humans, thus limiting use thereof in compositions to be administrated to human hosts.

According to present invention a stabilized composition comprising organic substrates such as pharmaceuticals and biological systems has been provided. The stabilized composition is characterized in that it contains inositoltriphosphate, IP₃, in a stabilizing amount.

The appropriate stabilizing amount of IP₃ should be determined by routine experimentation to obtain optimum values. For example accelerated aging test can be performed with a test substrate at various levels of IP₃ and the optimum level be determined thereby. In general, at least 0.001% by weight of IP₃ based on the weight of the composition will provide some beneficial effect. Usually from 0.01-2% by weight will be employed.

The stabilizer is mainly intended to be used against degradation caused by free radicals. Such free radicals can be formed in different ways, for instance by metals, such as iron, aluminium and cadmium, and by radiation.

However, the stabilizer is intended also to be used against degradation caused by oxidation and hydrolysis. The oxidation can be caused by free radicals as mentioned above. However, oxidation can depend on other mechanisms too. Therefore, the invention covers stabilization against oxidation, hydrolysis or radiation, whatever mechanism lies behind said reaction.

The stabilizer can be used for stabilizing many different pharmaceuticals, of which insulin, vaccines, hyaluronic acid, intralipid, prostaglandin and hormones can be mentioned.

Also a lot of different biological materials can be stabilized according to the invention. However, preferably the biological material is selected from DNA, recombinant DNA, RNA, nucleic acids, biological tissue, transplants, carbohydrates, lipids, membranes, proteins, such as enzymes and plasma proteins, culture media for micro-organisms, cell culture media, blood containing substrates, blood for transfusion, nutrient substrates, insemination media, micro-organisms, seeds, plant parts, spores, fruits and food stuffs.

According to one suitable method for the production of IP₃ a material containing IP₆ is broken down enzymatically with phytase enzyme. The IP₆ can be provided either as pure material or in the form of an IP₆ containing source, such as wheat bran. Phytase enzyme can be found for instance in plants, seeds and micro-organisms.

By the enzymatic treatment of the IP₆ a hydrolysis takes place resulting in a mixture of different lower inositolphosphates, i.e., inositolpentaphosphate (IP₅), inositoltetraphosphate (IP₄), inositoltriphosphate (IP₃), inositoldiphosphate (IP₂) and inositolmonophosphate (IP₁).

Usually, the hydrolysis is carried out at a temperature of 20°-70° C. and a pH of 4 to 8. The hydrolysis is suitably stopped when the liberation of about 30-60% of the total ester phosphorus has been achieved. At said stage a high proportion of the desired IP₃ isomer or isomers has been formed by hydrolysis of the IP₆ containing material.

The mixture of inositolphosphates obtained may hereafter be separated by chromatography to isolate the IP₃ -containing fraction. Preferably, this is made in a column. If the IP₃ fraction contains more than one isomer, these isomers are separated in another subsequent chromatographic separation step.

The IP₃ can be obtained as a salt or as an acid thereof. The salt form is preferred, since it is easier to produce in pure and concentrated form than the acid.

The salt form of the IP₃ isomer is readily obtainable from the acid form using standard procedures. Thus, there can be prepared salts, such as alkali metal and alkaline earth metal salts, e.g. lithium, sodium, potassium, calcium or magnesium. However, also the aluminium, zinc and iron salts are very useful as well as the NH₄ ⁺ and organic amine salts. Exemplary amines are triethanolamine, diethanolamine, triisopropanolamine, N,N-dimethyl-2-amino-2-methyl-1-propanol, N,N-dimethylethanolamine, tetrabutylamine and cyclohexylamine. Also other salts might be used. Especially preferred salts are those which are physiologically acceptable.

The invention is not restricted to any particular isomer of IP₃. Consequently, all individual isomers of IP₃ and mixtures thereof are included in the above definition, IP₃. However, preferably the stabilized composition comprises at least one of D-myo-inositol-1.2.6-triphosphate, D-myo-inositol-1.2.5-triphosphate, myo-inositol-1.2.3-triphosphate, D-myo-inositol-1.4.5-triphosphate and L-myo-inositol-1.3.4-triphosphate. Of these isomers D-myo-inositol-1.2.6-triphosphate is preferred.

When using yeast, preferably baker's yeast as a phytase source, only one isomer of IP₃ is obtained; namely D-myo-inositol-1.2.6-triphosphate. Especially when the composition comprises pharmaceuticals it is generally preferred to use the isomer or isomers of IP₃ in substantially pure form. The stabilizer component of the composition can consist wholly or essentially of IP₃.

The stabilizer is non-toxic and very efficient.

Sometimes the composition can also contain a minor amount of another inositolphosphate, especially inositoldiphosphate, IP₂ and inositoltetraphosphate, IP₄ in addition to IP₃. This is particularly the case where seeds, plant parts, spores, fruits and foodstuff are to be stabilized according to the invention. IP₂ and IP₄ can be presented in acid as well as in salt form.

The IP₃ -isomers mentioned above have the following formulas:

D-myo-inositol-1.2.6-triphosphate of the formula ##STR1## where X is hydrogen, at least one univalent, divalent or multivalent cation, or a mixture thereof, n is the number of ions, and z is the charge of the respectively ion; D-myo-inositol-1.2.5-triphosphate of the formula ##STR2## where X, n and z have the above mentioned meaning; myo-inositol-1.2.3-triphosphate of the formula ##STR3## where X, n and z have the above mentioned meaning; L-myo-inositol-1.3.4-triphosphate of the formula ##STR4## where X, n and z have the above mentioned meaning; and D-myo-inositol-1.4.5-triphosphate of the formula ##STR5## where X, n and z have the above meaning.

In each of the above formulas n ranges between 6 to 1 inclusive and z ranges from 1 to 6 inclusive. Preferably, n is between 3 to 6 inclusive and z is 3, 2 or 1.

For purposes of further understanding the invention, formulas are given below of some of the IP₃ -isomers of the invention. Formulas are also given for IP₆, IP₅, IP₄ and IP₂.

The lower phosphate-esters of myoinositol are named depending on where the phosphoric acid groups are situated on the inositol ring, with the numbering giving as low position numbers as possible. L and D stand for clockwise and counterclock-wise counting respectively, and are used depending on which result gives the lowest position number. The carbon atom which has an axial phosphoric acid group always has the position number 2. The structural formulae below are simplified to the acid form.

    ______________________________________                                          ##STR6##        myo-inositol; C.sub.6 H.sub.6 (OH).sub.6                       ##STR7##                                                                       ##STR8##        1.2.3.4.5.6-hexakis-(dihydrogen- phosphate)-myo-inositol                       alterna- tively myo-inositol hexakis (phosphate) or                            IP.sub.6                                                       ##STR9##        D-myo-inositol-1.2.6-triphosphate alternatively                                D-1.2.6-IP.sub.3                                               ##STR10##       D-myo-inositol-1.2.5-tri- phosphate alternatively                              D-1.2.5-IP.sub.3                                               ##STR11##       myo-inositol-1.2.3-tri- phosphate alternatively 1.2.3-IP.                      sub.3                                                         P = OPO.sub.3 H.sub.2                                                           ##STR12##       L-myo-inositol-1.3.4-tri- phosphate alternatively                              L-1.3.4-IP.sub.3                                               ##STR13##        L-myo-inositol-1.2-diphos- phosphate alternatively                            L-1.2-IP.sub.2                                                 ##STR14##       D-myo-inositol-1.2.5.6- tetra-phosphate or D-1.2.5.                            6-IP.sub.4                                                     ##STR15##       L-myo-inositol-1.2.3.4.5- penta phosphate                                      or L-1.2.3.4.5-IP.sub.5                                       P = OPO.sub.3 H.sub.2                                                          ______________________________________                                    

These IP compounds are described and prepared in applicant's copending U.S. patent application, Ser. No. 788,829 filed Oct. 18, 1985.

Other isomers of inositol triphosphate within the contemplation of the present invention include compounds having the structural formula ##STR16##

One group of inositol triphosphate compounds are defined by structural formula (I) where three of R₁, R₃, R₅, R₇, R₁₀ and R₁₁ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen.

Another group of inositol triphosphates are defined by structural formula (I) where three of R₁, R₃, R₆, R₇, R₉ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₅, R₈, R₁₀ and R₁₁ are hydrogen.

Still another group of inositol triphosphates are defined by structural formula (I) where three of R₁, R₃, R₅, R₈, R₁₀ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen.

Yet another group of inositol triphosphates are defined by structural formula (I) where three of R₁, R₄, R₅, R₈, R₉ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₃, R₆, R₇, R₁₀ and R₁₁ are hydrogen.

Still yet another group of inositol triphosphates are defined by structural formula (I) where three of R₁, R₃, R₆, R₈, R₉ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₅, R₇, R₁₀ and R₁₁ are hydrogen.

Even still another group of inositol triphosphates are defined by structural formula (I) where three of R₁, R₃, R₆, R₇, R₁₀ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₅, R₈, R₉ and R₁₁ are hydrogen.

Even yet group of inositol triphosphates are defined by structural formula (I) where three of R₁, R₃, R₅, R₈, R₁₀ and R₁₁ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₆, R₇, R₉ and R₁₂ are hydrogen.

Finally, another group of inositol triphosphates are defined by structural formula (I) where three of R₁, R₃, R₅, R₇, R₉ and R₁₁ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₆, R₈, R₁₀ and R₁₂ are hydrogen.

Particular inositol triphosphate compounds within the contemplation of the above groups include compounds having the structural formula (I) where

R₅, R₇ and R₁₀ are phosphate, R₁, R₃ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen;

R₁, R₁₀ and R₁₁ are phosphate, R₃, R₅ and R₇ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen;

R₁, R₃ and R₁₁ are phosphate, R₅, R₇ and R₁₀ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen;

R₃, R₅ and R₇ are phosphate, R₁, R₁₀ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen;

R₃, R₇ and R₁₀ are phosphate, R₁, R₅ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen;

R₃, R₁₀ and R₁₁ are phosphate, R₁, R₅ and R₇ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen;

R₁, R₃ and R₆ are phosphate, R₇, R₉ and R₁₂ are hydroxyl and R₂, R₄, R₅, R₈, R₁₀ and R₁₁ are hydrogen;

R₆, R₇ and R₉ are phosphate, R₁, R₃ and R₁₂ are hydroxyl and R₂, R₄, R₅, R₈, R₁₀ and R₁₁ are hydrogen;

R₃, R₅ and R₈ are phosphate, R₁, R₁₀ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen;

R₁, R₃ and R₁₂ are phosphate, R₅, R₈ and R₁₀ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen;

R₁, R₃ and R₅ are phosphate, R₈, R₁₀ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen;

R₁, R₅ and R₈ are phosphate, R₃, R₁₀ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen;

R₁, R₅ and R₁₂ are phosphate, R₃, R₈ and R₁₀ are hydroxyl and R₂, R₄, R₆, R₇, R₉ an R₁₁ are hydrogen;

R₁, R₃ and R₁₂ are phosphate, R₆, R₈ and R₉ are hydroxyl and R₂, R₄, R₅, R₇, R₁₀ and R₁₁ are hydrogen;

R₁, R₃ and R₆ are phosphate, R₇, R₁₀ and R₁₂ are hydroxyl and R₂, R₄, R₅, R₈, R₉ and R₁₁ are hydrogen;

R₄, R₅ and R₈ are phosphate, R₁, R₉ and R₁₂ are hydroxyl and R₂, R₃, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₃, R₅ and R₈ are phosphate, R₁, R₁₀ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₂ are hydrogen;

R₁, R₃ and R₅ are phosphate, R₈, R₁₀ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₂ are hydrogen;

R₁, R₃ and R₅ are phosphate, R₇, R₉ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₈, R₁₀ and R₁₂ are hydrogen;

R₁, R₃ and R₁₂ are phosphate, R₅, R₈ and R₉ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₁, R₃ and R₈ are phosphate, R₅, R₉, R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₃, R₅ and R₁₂ are phosphate, R₁, R₈ and R₉ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₁, R₅ and R₉ are phosphate, R₃, R₈ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₁, R₅ and R₁₂ are phosphate, R₃, R₈ and R₉ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₁, R₃ and R₉ are phosphate, R₅, R₈ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₁, R₈ and R₉ are phosphate, R₃, R₅ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₁, R₈ and R₁₂ are phosphate, R₃, R₅ and R₉ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₅, R₈ and R₁₂ are phosphate, R₁, R₃ and R₉ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₁, R₉ and R₁₂ are phosphate, R₃, R₅ and R₈ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₅, R₈ and R₉ are phosphate, R₁, R₃ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₃, R₈ and R₉ are phosphate, R₁, R₅ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₃, R₉ and R₁₂ are phosphate, R₁, R₅ and R₈ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;

R₃, R₈ and R₁₂ are phosphate, R₁, R₅ and R₉ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; and

R₈, R₉ and R₁₂ are phosphate, R₁, R₃ and R₅ are hydroxyl and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen.

The above discussed compounds having structural formula (I) are made by the same procedure set forth in Examples 19 to 22.

The invention will be explained further in detail in connection with the embodiment examples below, of which examples 1-5 show that IP₃ prevents or reduces the formation of free radicals. Example 6 illustrates preservation of some fruits and vegetables at the addition of IP₃. Example 7 shows that an addition of IP₃ to an enzyme gives a remarkable retention of the enzyme activity at storage. Examples 8-14 show production of IP₃ and the separation thereof into different isomers.

EXAMPLE 1

An aqueous solution containing 0.3 mM FeCl₃, 5.0 mM ethylenediaminotetraacetic acid (EDTA), 50 mM tris(hydroxymethyl)-aminomethan (TRIS) and 1.0M NaN₃ was prepared. In the solution the complex Fe³⁺ -EDTA-N₃ was formed.

A maximum in absorption of light was detected at the wavelength of 409 nm.

Another aqueous solution containing 0.3 mM FeCl₃, 50 mM EDTA and 50 mM TRIS was prepared. In the solution the complex Fe³⁺ -EDTA-H₂ O was formed. There was no maximum in absorption of light detected at the wavelength of 409 nm.

The above difference in result depends on that N₃ ⁻ competitively replaces one water molecular which binds to the Fe³⁺ -EDTA-complex. This in turn shows that the Fe³⁺ -EDTA-complex has a binding site, which is occupied by a dissociable water-molecule.

It is further known that iron catalyses the formation of hydroxylradicals. For the formation of these the binding of one water molecule to iron is required.

This means that EDTA in the EDTA-Fe³⁺ -complex can not inhibit the formation of hydroxyl radicals catalysed by iron.

The above experiment was repeated with the difference that the EDTA was substituted with IP₃.

No maximum in absorption was obtained at the wavelength 409 nm.

This result means that the Fe³⁺ -complex with IP₃ does not bind water. Therefore the formation of free radicals is prevented.

EXAMPLE 2

A reaction mixture consisting of 48 mmol KH₂ PO₄, 2 mmol Na-ascorbate, 0.1 mmol H₂ O₂, 0.5 mmol Fe and 1.7 mmol deoxyribose was incubated at 37° C. for 1 hour. Similar reactions mixtures including EDTA 1 mmol or inositol-tri-phosphate (IP₃) 1 mmol were similarly incubated. The IP₃ used was D-myo-inositol-1.2.6-triphosphate.

After incubation 1.65 ml thiobarbituric acid in 50 mmol NaOH and 1.65 ml 2.8% of trichloroacetic acid was added to 2 ml of the reaction mixture. The mixture was heated to 100° C. for 20 minutes and the absorbance at 532 nm was measured with water as a blank.

The experiments were performed with iron in the form of Fe²⁺ (Fe(NH₄)SO₄) and Fe³⁺ (FeCl₃). The results were as follows:

Production of free radicals catalyzed by Fe²⁺ and Fe³⁺ in the presence of IP₃ or EDTA, expressed as absorbance at 532 nm.

    ______________________________________                                         Group            Fe.sup.2+                                                                             Fe.sup.3+                                              ______________________________________                                         Control          0.76   0.79                                                   EDTA             2.2    1.86                                                   IP.sub.3         0.46   0.43                                                   ______________________________________                                    

These results show that the formation of free radicals in the reaction mixture was diminished by 40% after addition of IP₃. The addition of EDTA had an opposite effect. It strongly increased production of free radicals. Thus IP₃ was shown to reduce iron-dependent formation of free radicals.

EXAMPLE 3

Lipid peroxidation was studied in lipid micelles. The following reaction mixture was incubated for 2 hours at 37° C.:

    ______________________________________                                         0.4 ml         Clark-Lubs buffer pH 5.5                                        0.2 ml         phospholipid liposomes                                          0.1 ml         IP.sub.3 0.5-5 mM or 0.1 ml H.sub.2 O                           0.1 ml         Fe.sup.2+  1 mM or 0.1 ml H.sub.2 O                             0.1 ml         Al.sup.3+  4 mM or 0.1 ml H.sub.2 O                             0.1 ml         H.sub.2 O                                                       ______________________________________                                    

The IP₃ was D-myo-inositol-1.2.6-triphosphate. After incubation, 0.5 ml of thiobarbituric acid+0.5 ml 25% HCl was added and the mixture was heated at 100° C. for 15 minutes. 1 ml lubrol PX 1% (Sigma) was added and lipid peroxidation was measured by measuring absorbance at 532 nm. The results were as follows:

    ______________________________________                                         Concentration, mM                                                                                                Absorbance                                   Experiment Fe.sup.2+                                                                             Al.sup.3+  IP.sub.3                                                                            532 nm                                       ______________________________________                                         1          0.1    0          0    0.36                                         2          0      0.4        0    0.12                                         3          0.1    0.4        0    0.89                                         4          0.1    0.4        0.5  0.36                                         5          0.1    0          0.5  0.30                                         6          0.1    0          0.4  0.26                                         7          0.1    0          0.2  0.29                                         8          0.1    0          0.1  0.28                                         9          0.1    0          0.05 0.27                                         10         0      0          0    0.13                                         ______________________________________                                    

Fe²⁺ caused lipid peroxidation (group 1 vs 10). Al³⁺ itself caused no peroxidation (2 vs 10) whereas the combination of Fe²⁺ +Al³⁺ caused much stronger peroxidation than Fe²⁺ alone (1 vs 3). Addition of IP₃ completely prevented the interaction between Fe²⁺ and Al³⁺ (3 vs 4). In systems with only Fe²⁺, IP₃ causes marked reduction in radical formation (1 vs 5-9).

EXAMPLE 4

Lipid peroxidation was studied in lipid micelles. The following reaction mixture was incubated for 2 hours at 37° C.:

    ______________________________________                                         0.4 ml   Clark-Lubs buffer pH 5.5                                              0.2 ml   phospholipid liposomes                                                0.1 ml   IP.sub.3 10 mM or 0.1 ml H.sub.2 O                                    0.1 ml   Fe.sup.2+  1 mM                                                       0.1 ml   Cd.sup.2+ 1 mM or 1 ml Pb.sup.2+  1 mM or 0.1 ml H.sub.2 O            0.1 ml   H.sub.2 O                                                             ______________________________________                                    

The IP₃ was D-myo-inositol-1.2.6-triphosphate. After incubation, of 0.5 ml of thiobarbituric acid+0.5 ml 25% HCl was added and the mixture was heated at 100° C. for 15 minutes. 1 ml Lubrol PX 1% (Sigma) was added and lipid peroxidation was measured by measuring absorbance at 532 nm. The results were as follows:

    ______________________________________                                         Concentration, mM                                                                                                Absorbance                                   Experiment Cd.sup.2+                                                                             Pb.sup.2+  IP.sub.3                                                                            532 nm                                       ______________________________________                                         1          0      0          0    0.63                                         2          0.1    0          0    1.08                                         3          0.1    0          1.0  0.73                                         4          0      0.1        0    1.79                                         5          0      0.1        1.0  1.32                                         ______________________________________                                    

The lipid peroxidation caused by Fe²⁺ (group 1) was strongly increased by Cd (2) and by Pb (4). The effects of both these metals was strongly counteracted by IP₃ (3 vs 2 and 5 vs 4).

EXAMPLE 5

Reaction mixtures with the following compositions were incubated for 5 minutes at 37° C.:

    ______________________________________                                         KH.sub.2 PO.sub.4 buffer pH 7.4                                                                    20         mM                                              EDTA                0.1        mM                                              Salicylate          1          mM                                              Ascorbate           1          mM                                              H.sub.2 O.sub.2     3.3        mM                                              Fe.sup.3+           0.05       mM                                              IP.sub.3            0, 2.5, 5 or 10                                                                           mM                                              ______________________________________                                    

The products formed by oxidation of salicylate were quantified with HPLC. The IP₃ was D-myo-inositol-1.2.6-triphosphate.

The system studies radical scavenging. Under these reaction conditions, all Fe³⁺ will form complex with EDTA. The Fe-EDTA complex will induce free radical formation, and the ability of IP₃ to prevent oxidation of salicylate is studied.

The results of the experiment were:

    ______________________________________                                         Concentration Relative amount of                                               of IP.sub.3, mM                                                                              salicylate oxidized                                              ______________________________________                                         0             100                                                              2.5           44                                                               5             43                                                               10            19                                                               ______________________________________                                    

Thus, IP₃ is able to act as a radical scavenger, thereby preventing free radical induced damage to other molecules.

EXAMPLE 6

Preservation of some fruits and vegetables at the addition of IP₃.

4 g of fresh potatoes, bananas and apples respectively were sliced in 10 pieces each. 5 pieces of the same fruit or vegetable were put into each of 5 different beakers. Three of the beakers were filled with 15 ml of an aqueous solution of IP₃ and three additional beakers with 15 ml of an aqueous solution of IP₆, in such a way that each 5 pieces of fruit and vegetable were exposed either to pure water or water with IP₃ and IP₆ respectively. The content of IP₃ and IP₆ respectively in the water was 1.0 g/l.

The samples were allowed to stand in room temperature for 15 hours. After this period the colour of the samples was inspected and the following data were found:

    ______________________________________                                                Potato    Banana      Apple                                             ______________________________________                                         No IP.sub.3 added                                                                       brown colour                                                                               brown colour                                                                               brown colour                                  IP.sub.3 added                                                                          very slight very slight slight brown                                           brown       brown                                                     IP.sub.6 added                                                                          brown colour                                                                               brown colour                                                                               brown colour                                  ______________________________________                                    

The results show that IP₃ has a preservative effect on the fruits and vegetables investigated, whereas IP₆ has no such effect.

EXAMPLE 7

Enzyme activity at the addition of IP₃.

The activity of aldolase with respectively without addition of IP₃ was measured as a function of time.

Aldolase degrades fructose-1.6-diphosphate (FDP) as dihydroxyacetonephosphate. This substrate is further reacted by α-glycerophosphatedehydrogenase (GDH) in the presence of nicotinamide adenine dinucleotide, reduced from (NADH) to α-glycerophosphate and nicotinamide adenine dinucleotide, oxidized form (NAD). By measuring the decline of the UV-absorption at 340 nm for the reaction NADH to NAD the activity of the enzyme is determined.

The aldolase was stored at 25° C. and the activity was measured initially and after 72 hours with and without additional of IP₃ (4 g/l).

0.5 ul aldolase (A1893 from Sigma Chemical Co, 0.2 U/ml) was mixed with 2.75 ml of a buffer pH 7.5 consisting of 0.10 g KH₂ PO₄, 0.74 K₂ HPO₄, 1.96 KCH₃ CH₂ OO, 50 mg FDP and 8 mg NADH per 100 ml buffer. 1.47 ul GDH was further added and the total volume was diluted to 3.0 ml. The determination of the activity was performed at 30° C.

The following results were obtained:

    ______________________________________                                         Time                                                                           for storage                                                                               No Ip.sub.3                                                                            IP.sub.3                                                    at 25° C.                                                                          added   added                                                       ______________________________________                                          0         0.12    0.12 decline of absorbance/min                              72 hours   0.05    0.07 decline of absorbance/min                              ______________________________________                                    

The results show that the activity of the enzyme was improved by about 40% after addition of IP₃ when the activity was determined after 72 hours storage at 25° C.

EXAMPLE 8

Hydolysis of sodium phytate with wheat phytase and fractionation of a mixture of inositolphosphates.

A 1.6 gram quantity of sodium phytate (from corn, Sigma Chemical Co) was dissolved in 650 ml sodium acetate buffer, pH 5.2. 2.7 gram wheat phytase (EC 3.1.3.26, 0.015 U/mg, from Sigma Chemical Co) was added and the mixture was incubated at 38° C.

The dephosphorylation was followed by determining the inorganic phosphorus released. After 3 hours when 50% inorganic phosphorus was liberated the hydrolysis was stopped by adding 30 ml ammonia to pH 12. A liquid mixture containing inositolphosphates was obtained.

350 ml of the mixture was passed through an ion-exchange column (Dowex 1, chloride form, 25 mm×250 mm) and eluted with a linear gradient of hydrochloric acid (0-0.7N HCl). Aliquots of eluted fractions were completely hydrolyzed in order to determine the contents of phosphorus and inositol. The peaks correspond to different inositolphosphates i.e. a peak with the ratio of phosphorus to inositol of three to one consists of inositoltriphosphate etc. Two fractions with the ratio of phosphorus to inositol of three to one were obtained.

EXAMPLE 9

Fractionation of inositoltriphosphates.

100 ml of the first fraction obtained in Example 8 with a phosphorus/inositol ratio of three to one was neutralized and precipitated as a bariumsalt after addition of 10% excess of 0.1M bariumacetate solution. 600 mg of the precipitated salt was dissolved in 50 ml 0.18N hydrochloric acid. The solution was separated on an ion-exchange column (Dowex 1, chloride form, 25 mm×2500 mm) with diluted hydrochloric acid as eluent. Aliquots of eluted fractions were analyzed for phosphorus. Three peaks consisting of isomers of inositoltriphosphates can be seen. EXAMPLE 10

Structural determination of isomers of inositol-triphosphates with NMR.

The three peaks obtained in Example 9 were analyzed by H-NMR. Data show that the peaks consist of myo-inositol-1.2.6-triphosphate, myo-inositol-1.2.3-triphosphate and myo-inositol-1.3.4-triphosphate respectively.

The second fraction obtained in Example 18 with a phosphorus/inositol ratio of three to one was analyzed by H-NMR. Data show that the fraction consists of myo-inositol-1.2.5-triphosphate.

EXAMPLE 11

Determination of optical isomers of inositol-triphosphates.

20 mg of the compounds determined with NMR according to Example 10 to be myo-inositol-1.2.6-triphosphate and myo-inositol-1.3.4-triphosphate were further chromatographed on a chiral column based on acetylated cellulose (20 mm×300 mm from Merck) with a mixture of ethanol and water as eluent. The fractions were analyzed with a polarimeter. As can be seen each compound consists of one optical isomer, D-myo-inositol-1.2.6-triphosphate and L-myo-inositol-1.3.4-triphosphate respectively.

EXAMPLE 12

Hydrolysis of sodium phytate with baker's yeast and fractionation of a mixture of inositolphosphates.

A 0.7 gram quantity of sodium phytate (from corn, Sigma Chemical Co) was dissolved in 600 ml sodium acetate buffer pH 4.6. 50 gram of baker's yeast from Jastbolaget, Sweden (dry substance: 28%, nitrogen content: 2%; phosphorus content: 0.4%) was added with stirring and incubation was continued at 45° C. The dephosphorylation was followed by determining the inorganic phosphorus released. After 7 hours when 50% inorganic phosphorus was liberated the hydrolysis was stopped by adding 30 ml of ammonia to pH 12. The suspension was centrifuged and the supernatant was collected.

400 ml of the supernatant was passed through an ion-exchange column (Dowex 1, chloride form, 25 mm×250 mm) and eluted with a linear gradient of hydrochloric acid (0-0.7N HCl).

Aliquots of eluted fractions were completely hydrolyzed in order to determine the contents of phosphorus and inositol. The peaks correspond to different inositolphosphates i.e. a peak with the ratio of phosphorus to inositol of three to one consists of inositoltriphosphates etc.

EXAMPLE 13

Structural determination of isomers of inositoltriphosphate.

The fraction obtained in Example 12 with a phosphorus/inositol ratio of three to one was neutralized and evaporated before analysis with H-NMR. Data show that the peak consists of myo-inositol-1.2.6-triphosphate.

EXAMPLE 14

Determination of optical isomers of myo-inositol-triphosphate.

The same method was used as described in Example 11 with the difference that 10 mg of the compound determined with NMR according to Example 13 was analyzed. As can be seen the compound consists of one optical isomer, D-myo-inositol-1.2.6-triphosphate.

EXAMPLE 15

A reaction mixture containing, in a final volume of 2 ml, the following reagents: 50 mM KH₂ PO₄ buffer (pH=7.4), 0.5 mM Ascorbate, 0.05 mM Fe³⁺, 0.2 mM or 0.5 mM H₂ O₂ and 1.7 mM Deoxyribose was incubated at 37° C. for 1 hour. Similar reaction mixtures including 0.5 mM or 1.0 mM D-myo-inositol-1.2.6-triphosphate were similarly incubated.

After incubation 1.65 ml 1% (w/v) thiobarbituric acid in 50 mM NaOH and 1.65 ml 2.8% (w/v) trichloroacetic acid were added. The mixture was healed to 100° C. for 20 minutes and the absorbance at 532 nm was measured against water as a blank.

Production of free radicals catalyzed by Fe³⁺ in presence of different concentrations of IP₃ expressed as absorbance at 532 nm gave the following results:

    ______________________________________                                         Group               Absorbance                                                 ______________________________________                                         0.2 mM H.sub.2 O.sub.2 Control                                                                     0.322                                                      0.2 mM H.sub.2 O.sub.2 + 0.5 mM IP.sub.3                                                           0.153                                                      0.2 mM H.sub.2 O.sub.2 + 1.0 mM IP.sub.3                                                           0.130                                                      0.5 mM H.sub.2 O.sub.2 Control                                                                     0.553                                                      0.5 mM H.sub.2 O.sub.2 + 0.5 mM IP.sub.3                                                           0.332                                                      0.5 mM H.sub.2 O.sub.2 + 1.0 mM IP.sub.3                                                           0.324                                                      ______________________________________                                    

These results show that at 0.2 mM H₂ O₂ addition of 0.5 mM IP₃ diminish the production of free radicals by 50% and 1.0 mM IP₃ diminish it by 60%. At 0.5 mM H₂ O₂ both 0.5 mM and 1.0 mM IP₃ decreased the radical production by 40%.

EXAMPLE 16

A reaction mixture containing, in a final volume of 2 ml, the following reagents: 50 mM KH₂ PO₄ buffer (pH=7.4), 0.05 mM Fe³⁺, 2.0 mM Deoxyribose, 0.3 mM Hypoxantine and 42 mU/ml Xantineoxidase was incubated at 37° C. for 1 hour. The blanks were incubated in the absence of enzyme. Similar reaction mixtures including 0.2 mM, 0.5 mM or 1.0 mM D-myo-inositol-1.2.6-triphosphate were similarly incubated.

After incubation 1.65 ml 1% (w/v) thiobarbituric acid in 50 mM NaOH and 1.65 ml 2.8% (w/v) trichloroacetic acid was added. To the blanks was also Xantineoxidase added. The mixtures were heated at 100° C. for 20 minutes and the absorbance at 532 nm was measured.

Production of free radicals formed by Xantineoxidase and catalyzed by Fe³⁺ in the presence of IP₃ gave the following results:

    ______________________________________                                                     Absorbance                                                                     (difference between                                                Group       reaction mixture and blank)                                        ______________________________________                                         Control     0.339                                                              0.2 mM IP.sub.3                                                                            0.232                                                              0.5 mM IP.sub.3                                                                            0.153                                                              1.0 mM IP.sub.3                                                                            0.108                                                              ______________________________________                                    

The results show that IP₃ inhibits also the enzyme catalyzed free radical formation. The efficiency of the inhibition depends on the concentration of IP₃.

EXAMPLE 17

A reaction mixture containing, in a final volume of 1 ml, the following reagents: 50 mM TRIS buffer (pH=7.4), 0.05 mM Fe³⁺, 50 mM DMSO (dimethylsulfoxide), 0.3 mM Hypoxantine and 18 mU Xantineoxidase was incubated at 37° C. for 30 minutes. The blanks were incubated in the absence of enzyme. Similar reaction mixture including 0.5 mM D-myo-inositol-1.2.6-triphosphate was similarly incubated.

Reaction was terminated by the addition of 50 ul 100% trichloroacetic acid. Xantineoxidase was then added to the blanks. Formation of formaldehyde was measured by addition of 1.05 ml Hantzsch solution (Hantzsch solution consists of 50 mM acetic acid, 20 mM acetylacetone and 2M ammoniumacetate). The mixtures were then incubated 40 minutes at 37° C. and the absorbance was measured at 412 nm.

Production of free radicals formed by Xantineoxidase and catalyzed by Fe³⁺ in the presence of IP₃ gave the following results.

    ______________________________________                                                     Absorbance                                                                     (difference between                                                Group       reaction mixture and blank)                                        ______________________________________                                         Control     0.072                                                              0.5 mM IP.sub.3                                                                            0.008                                                              ______________________________________                                    

These results show a nearly complete 90% inhibition of the free radical formation.

EXAMPLE 18

A reaction mixture containing, in a final volume of 2 ml, the following reagents: 50 mM TRIS buffer (pH=7.4), 0.5 mM Ascorbate, 0.05 mM Fe³⁺, 0.5 mM H₂ O₂ and 5 mM DMSO was incubated at 37° C. for 1 hour. Similar reaction mixtures including 0.5 mM or 1.0 mM D-myo-inositol-1.2.6-triphosphate were similarly incubated.

After incubation 0.1 ml 90% Trichloroacetic acid and 2.1 ml Hantzsch solution was added. (Hantzsch solution consists of 50 mM acetic acid, 20 mM acetylacetone and 2M ammoniumacetate). The samples were then incubated 40 minutes at 37° C. and the absorbance was measured at 412 nM against water as a blank.

Production of free radicals catalyzed by Fe³⁺ in presence of different concentrations of IP₃ expressed as absorbance at 412 nm gave the following results:

    ______________________________________                                         Group         Absorbance                                                       ______________________________________                                         Control       0.445                                                            0.5 mM IP.sub.3                                                                              0.351                                                            1.0 mM IP.sub.3                                                                              0.323                                                            ______________________________________                                    

Also in this system the results show that the formation of free radicals was inhibited by IP₃, at 0.5 mM IP₃ to 20% and at 1.0 mM IP₃ to 30%.

EXAMPLE 19

A 0.5 gram quantity of D-chiro-inositol was dissolved in 1 mL phosphoric acid at 60° C. 20 g polyphosphoric acid was added and the mixture was heated to 150° C. under vacuum for 6 hours. The mixture was diluted with water to a volume of 200 ml and passed through an ion-exchange column (Dowex 1, chloride form, 25 mm×250 mm) and eluted with a linear gradient of hydrochloric acid (0-2.0N HCl).

The content of the peak with the ratio of phosphorus to inositol of six to one was precipitated by addition of calciumhydroxide. The precipitate was filtered, washed and mixed with 10 ml of a cation-exchange resin to give the acid form of the inositolhexaphosphate. After neutralization with sodium hydroxide and freeze-drying the sodiumsalt of D-chiro-inositolhexaphosphate was obtained.

EXAMPLE 20

A 0.8 gram quantity of the sodium salt of D-chiro-inositolhexaphosphate produced according to Example 19 was dissolved in 300 ml sodium acetate buffer, pH 5.2. 1.3 gram wheat phytase (EC 3.1.3.26 0.015 U/mg from Sigma Chemical Co.) was added and the mixture was incubated at 38° C.

After the liberation of 50% inorganic phosphorus the hydrolysis was stopped by adding ammonia to pH 12.

The mixture containing D-chiro-inositolphosphates was passed through an ion-exchange column (Dowex 1 chloride form, 25 mm×250 mm) and eluted with a linear gradient of hydrochloric acid (0-0.7N HCl).

The peak with the ratio of phosphorus to inositol of three to one was neutralized with 1.0M sodium hydroxide and freeze-dried.

Structural determination with NMR and IR showed the product to be D-chiro-inositoltriphosphate.

EXAMPLE 21

A 0.8 gram quantity of epi-inositol was dissolved in 1.5 ml of phosphoric acid at 60° C. 32 g polyphosphoric acid was added and the mixture was heated to 150° C. under vacuum for 6 hours. The mixture was diluted with water to a volume of 200 ml and passed through an ion-exchange column (Dowex 1, chloride form, 25 mm×250 mm) and eluted with a linear gradient of hydrochloric acid (0-2.0N HCl).

The content of the peak with the ratio of phosphorus to inositol of six to one was precipitated by addition of calcium hydroxide. The precipitate was filtered, washed and mixed with 10 ml of a cation-exchange resin to give the acid form of the inositol hexaphosphate. After neutralization with sodium hydroxide and freeze-drying the sodium salt of epi-inositolhexaphosphate was obtained.

EXAMPLE 22

A 1.2 gram quantity of the sodium salt of epi-inositolhexaphosphate produced according to Example 21 was dissolved in 500 ml sodium acetate buffer, pH 5.2. 2.0 gram wheat phytase (EC 3.1.3.26, 0.015 U/mg from Sigma Chemical Co.) was incubated at 38° C.

After the liberation of 50% inorganic phosphorus the hydrolysis was stopped by adding ammonia to pH 12.

The mixture containing epi-inositolphosphates was passed through an ion-exchange column (Dowex 1, chloride form, 25 mm×250 mm) and eluted with a linear gradient of hydrochloric acid (0-0.7N HCl).

The peak with the ratio of phosphorus to inositol of three to one was neutralized with 1.0M sodium hydroxide and freeze-dried.

Structural determination with NMR and IR showed the product to be epi-inositoltriphosphate. 

What is claimed is:
 1. A stabilized composition comprising an organic substrate subject to degradation by oxidation and/or free radical reaction and between about 0.01% to about 2% by weight, based on the total weight of the composition, of at least one isomer of inositol triphosphate, a salt thereof or an acid thereof, said isomer having the structural formula ##STR17## where (a) three of R₁, R₃, R₅, R₇, R₁₀ and R₁₁ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen;(b) three of R₁, R₃, R₆, R₇, R₉ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₅, R₈, R₁₀ and R₁₁ are hydrogen; (c) three of R₁, R₃, R₅, R₈, R₁₀ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen; (d) three of R₁, R₄, R₅, R₈, R₉ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₃, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (e) three of R₁, R₃, R₆, R₈, R₉ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₅, R₇, R₁₀ and R₁₁ are hydrogen; (f) three of R₁, R₃, R₆, R₇, R₁₀ and R₁₂ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₅, R₈, R₉ and R₁₁ are hydrogen; (g) three of R₁, R₃, R₅, R₈, R₁₀ and R₁₁ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₆, R₇, R₉ and R₁₂ are hydrogen; or (h) three of R₁, R₃, R₇, R₉ and R₁₁ are hydroxyl and the remaining three are phosphate and R₂, R₄, R₆, R₈, R₁₀ and R₁₂ are hydrogen.
 2. A composition according to claim 1 wherein R₅, R₇ and R₁₀ are phosphate, R₁, R₃ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen.
 3. A composition according to claim 1 wherein R₁, R₁₀ and R₁₁ are phosphate, R₃, R₅ and R₇ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen.
 4. A composition according to claim 1 wherein R₁, R₃ and R₁₁ are phosphate, R₅, R₇ and R₁₀ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen.
 5. A composition according to claim 1 wherein R₃, R₅ and R₇ are phosphate, R₁, R₁₀ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen.
 6. A composition according to claim 1 wherein R₃, R₇ and R₁₀ are phosphate, R₁, R₅ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen.
 7. A composition according to claim 1 wherein R₃, R₁₀ and R₁₁ are phosphate, R₁, R₅ and R₇ are hydroxyl and R₂, R₄, R₆, R₈, R₉ and R₁₂ are hydrogen.
 8. A composition according to claim 1 wherein R₁, R₃ and R₆ are phosphate, R₇, R₉ and R₁₂ are hydroxyl and R₂, R₄, R₅, R₈, R₁₀ and R₁₁ are hydrogen.
 9. A composition according to claim 1 wherein R₆, R₇ and R₉ are phosphate, R₁, R₃ and R₁₂ are hydroxyl and R₂, R₄, R₅, R₈, R₁₀ and R₁₁ are hydrogen.
 10. A composition according to claim 1 wherein R₃, R₅ and R₈ are phosphate, R₁, R₁₀ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen.
 11. A composition according to claim 1 wherein R₁, R₃ and R₁₂ are phosphate, R₅, R₈ and R₁₀ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen.
 12. A composition according to claim 1 wherein R₁, R₃ and R₅ are phosphate, R₈, R₁₀ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen.
 13. A composition according to claim 1 wherein R₁, R₅ and R₈ are phosphate, R₃, R₁₀ and R₁₂ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen.
 14. A composition according to claim 1 wherein R₁, R₅ and R₁₂ are phosphate, R₃, R₈ and R₁₀ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₁ are hydrogen.
 15. A composition according to claim 1 wherein R₁, R₃ and R₁₂ are phosphate, R₆, R₈ and R₉ are hydroxyl and R₂, R₄, R₅, R₇, R₁₀ and R₁₁ are hydrogen.
 16. A composition according to claim 1 wherein R₁, R₃ and R₆ are phosphate, R₇, R₁₀ and R₁₂ are hydroxyl and R₂, R₄, R₅, R₈, R₉ and R₁₁ are hydrogen.
 17. A composition according to claim 1 wherein R₄, R₅ and R₈ are phosphate, R₁, R₉ and R₁₂ are hydroxyl and R₂, R₃, R₆, R₇, R₁₀ and R₁₁ are hydrogen.
 18. A composition according to claim 1 wherein R₃, R₅ and R₈ are phosphate, R₁, R₁₀ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₂ are hydrogen.
 19. A composition according to claim 1 wherein R₁, R₃ and R₅ are phosphate, R₈, R₁₀ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₇, R₉ and R₁₂ are hydrogen.
 20. A composition according to claim 1 wherein R₁, R₃ and R₅ are phosphate, R₇, R₉ and R₁₁ are hydroxyl and R₂, R₄, R₆, R₈, R₁₀ and R₁₂ are hydrogen.
 21. A stabilized composition comprising an organic substrate subject to degradation by oxidation and/or free radical reaction and between about 0.01% to about 2% by weight, based on the total weight of the composition, of inositol triphosphate, said inositol triphosphate provided by at least one compound, a salt thereof or an acid having the structural formula ##STR18## where (a) R₁, R₃ and R₁₂ are phosphate; R₅, R₈ and R₉ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen;(b) R₁, R₃ and R₈ are phosphate; R₅, R₉ and R₁₂ are hydroxyl; and R₂, R₄, R₆, R₇ and R₁₀ and R₁₁ are hydrogen; (c) R₃, R₅ and R₁₂ are phosphate; R₁, R₈, and R₉ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (d) R₁, R₅ and R₉ are phosphate; R₃, R₈ and R₁₂ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (e) R₁, R₃ and R₉ are phosphate; R₅, R₈ and R₁₂ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (f) R₁, R₈ and R₉ are phosphate; R₃, R₅, and R₁₂ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (g) R₁, R₈ and R₁₂ are phosphates; R₃, R₅ and R₉ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (h) R₅, R₈ and R₁₂ are phosphate; R₁, R₃ and R₉ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (i) R₁, R₉ and R₁₂ are phosphate; R₃, R₅ and R₈ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (j) R₅, R₈ and R₉ are phosphate; R₁, R₃ and R₁₂ are hydroxyl; R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (k) R₃, R₈ and R₉ are phosphate; R₁, R₅ and R₁₂ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; (l) R₃, R₈ and R₁₂ are phosphate; R₁, R₅ and R₉ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀, and R₁₁ are hydrogen; (m) R₈, R₉ and R₁₂ are phosphate; R₁, R₃ and R₅ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen (n) R₁, R₅ and R₁₂ are phosphate; R₃, R₈ and R₉ are hydroxyl; and R₂, R₄, R₆, R₇, R₁₀ and R₁₁ are hydrogen; or (o) R₃, R₉ and R₁₂ are phosphate; R₁ and R₅ and R₈ are hydroxyl; and R₂, R₄, and R₆, R₇, R₁₀ and R₁₁ are hydrogen. 